The mousewheel default scroll delta speed in a locked grid has a different speed when hovering over the locked columns compared to the unlocked columns in Firefox 15 (and to a lesser degree IE9). The unlocked columns are very slow to scroll through. Visible in the locking example at http://docs.sencha.com/ext-js/4-1/ex...king-grid.html

Steps to reproduce the problem:

Position mouse over unlocked columns and use mousewheel to scroll. Compare speed when hovering over the locked side. When mousing over the unlocked columns the scroll speed is significantly reduced.

The result that was expected:

Scroll delta on the locked side of the grid and the unlocked side should be the same speed by default.

The result that occurs instead:

The scroll delta on the unlocked side is significantly slower in Firefox 15.01 when scrolling the mousewheel while hovering over the unlocked columns.